Dragonfly

Dragonfly is a modern in-memory data store designed as a drop-in replacement for Redis and Memcached, delivering significantly higher throughput and better resource efficiency through an innovative multi-threaded shared-nothing architecture. Written in C++ and utilizing a thread-per-core design, Dragonfly achieves up to 25 times more throughput on a single node compared to Redis, while maintaining full API compatibility with Redis commands, RESP protocol, and Memcached protocol. This allows existing applications using Redis or Memcached client libraries to switch to Dragonfly without any code changes. Key architectural innovations include a shared-nothing connection handling model where each thread owns its own set of connections and data shards, eliminating the need for locks and contention that limit Redis performance. The adaptive snapshotting mechanism (point-in-time snapshots that do not block writes) and efficient memory management enable Dragonfly to operate with up to 80 percent less resources than equivalent Redis deployments while maintaining lower tail latency and higher cache hit rates. Dragonfly supports advanced features including multi-key transactions, Lua scripting, publish/subscribe messaging, key expiration with lazy and active eviction policies, and cluster mode with automatic sharding. The project has gained massive community traction with over 30,800 GitHub stars and 1,200 forks, and is trusted by companies across gaming, social media, e-commerce, and financial services for high-throughput caching, session storage, real-time leaderboards, and rate limiting use cases. Dragonfly is available as open-source under the Business Source License (BSL) and as a fully managed Dragonfly Cloud service.